1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method. In particular, the present invention relates to an improved technique of a process for detecting the remaining amount of developer (hereinafter, referred to as “toner”).
2. Description of Related Art
In an image forming apparatus, a developing device for developing an electrostatic latent image with toner and visualizing the latent image as toner image is provided. In the image forming apparatus, a toner-supplying device for supplying the developing device with toner is equipped. The toner-supplying device temporarily stores toner which is supplied directly or from a toner bottle disposed in the image forming apparatus, in a hopper as a toner container. The toner-supplying device supplies developing device with toner through the hopper.
At the beginning of using the image forming apparatus or in case of refilling toner, toner does not have quantity of electric charge enough to form images. Therefore the density of formed image becomes uneven, which causes degradation of image quality.
As a method for making the quantity of electric charge up to the predetermined value quickly, the electrophotographic image forming apparatus for storing the total number of printing and the presence or absence of the-remaining-amount-detection signal in a read/write nonvolatile storage unit and for changing the operating condition of agitating mechanism in the hopper on the basis of the information stored in the nonvolatile storage unit is disclosed (JP-Tokukaihei-9-190078A).
In general, the presence or absence of toner is detected by a developer detector attached to the wall surface of the hopper. The developer detector is attached so that the detector plane faces toward the inside of the hopper and comes in contact with toner.
Meanwhile an agitating device agitating toner in the hopper in a cycle or at the proper timing is provided in the hopper in order to preventing retention of toner.
Many of agitating devices employ rotating mechanism that rotates in the hopper, and are constituted of mechanism that an agitating rod in which a flexible member having flexibility is provided at the end thereof rotates. The flexible member which slides on an internal surface of the hopper and moves rotationally, works as a blade for sweeping toner on the internal surface.
The above-mentioned configuration has a problem in that the flexible member slides on the detector plane of the developer detector with the rotation of the agitator, and in this sliding, there is some possibility of causing false detection of remaining amount of toner by covering the detector plane with the flexible member.
Because toner is transferred to the developing device with agitation, the level of the remaining toner declines so that the level repeatedly moves up and down by the agitation. Therefore in the case of the level near the detector plane which detects the presence or absence of toner, the detector performs detecting actions that frequent repetition of the presence or absence of toner is detected, such as the presence of toner is detected even though the absence of toner must be detected by rights, and the absence of toner is detected even though the absence of toner does not have to be detected by rights. In other words, chattering occurs in the outputted signal from the developer detector. Furthermore, the absence of toner is detected late in comparison with the actual remaining amount of toner.
The above-mentioned actions of false detection are factors that cause degradation of credibility of image forming apparatuses.